Metal fusion bonding – Process – Preplacing solid filler
Reexamination Certificate
1999-10-06
2001-05-22
Ryan, Patrick (Department: 1725)
Metal fusion bonding
Process
Preplacing solid filler
C228S038000, C228S044500, C228S044300
Reexamination Certificate
active
06234383
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for circumferential application of materials to an interior surface of a curved pipe
BACKGROUND OF THE INVENTION
There are various applications in which a circumferential application of materials to an interior surface of a pipe is preferred. For example, circumferential welding of overlay materials to an interior surface of a pipe is preferred, as fluids tend to flow along longitudinal welds and accelerate wear. It is relatively easy to circumferentially weld a section of straight pipe. When the section of pipe is curved, positioning a circumferential weld along the interior surface of the pipe becomes extremely difficult.
At the present time there is no cost effective method for positioning a circumferential weld along the interior surface of a curved section of pipe. Welds are, therefore, positioned longitudinally. In addition to accelerated wear, fit problems have been encountered due to differences in shrinkage between straight sections of pipe welded circumferentially and curved sections of pipe welded longitudinally.
SUMMARY OF THE INVENTION
What is required is a method and an apparatus for circumferential application of materials to an interior surface of a curved pipe.
According to one aspect of the present invention there is provided a method for circumferential application of materials to an interior surface of a curved pipe which includes the following steps. A pipe support is provided with a rotational axis. A curved section of pipe is mounted to the pipe support. A arm supporting an applicator head is positioned within the curved section of pipe. The pipe support is rotated about the rotational axis, while coordinating movement of the arm to maintain the applicator head in a working position within the curved section of pipe.
Although beneficial results may be obtained through the method, as described above, even more beneficial results may be obtained when the further step is taken of varying the rotational speed of the pipe support to control the rate of application or deposition of materials being applied.
Although beneficial results may be obtained through the use of the method, as described above, even more beneficial results may be obtained when the further step is taken of oscillating the applicator head and varying the oscillating amplitude of the applicator head to compensate for differences in length of curvature of the pipe.
According to another aspect of the invention there is provided an apparatus for circumferential application of materials to an interior surface of a curved pipe which includes a base and a pipe support mounted to the base for rotation about a rotational axis. The pipe support has a cavity adapted to receive a curved section of pipe. An arm extends into the cavity of the pipe support. An applicator head is mounted to the arm. A rotational drive is provided which is adapted to rotate the pipe support about the rotational axis. A controller is provided which is adapted to coordinate movement of the arm with the rotational positioning of the pipe support.
Although beneficial results may be obtained through the use of the apparatus, as described above, even more beneficial results may be obtained when the controller also coordinates the position of the applicator head with the rotational positioning of the pipe support. There are various ways to control the position of the applicator head there will hereinafter be further described a linkage which extends through the arm to the applicator head. The flexible linkage is adapted to control orientation of the applicator head.
Although beneficial results may be obtained through the use of the apparatus, as described above, even more beneficial results may be obtained when the pipe support includes longitudinal guides and a guidance source adapted to move a curved section of pipe along the longitudinal guides. It is difficult to coordinate this movement with the pipe support rotating. There will hereinafter be described a longitudinal guidance source which applies a linear pulling force and longitudinal guides which provide an arcuate guide path to compensate for the curvature of the pipe.
Although beneficial results may be obtained through the apparatus, as described above, even more beneficial results may be obtained when the applicator head oscillates and the amplitude of oscillation is variable. This allows the applicator head to compensate for differences in the length of curvature of the pipe. There will hereinafter be further described an oscillation control mechanism in which such oscillations are controlled by a movable sensor oscillating between a pair of angularly offset rotating swash plates carried by the rotating pipe support. The movable sensor has a master to slave relationship with an oscillating drive for the applicator head.
REFERENCES:
patent: 3585345 (1971-06-01), Jespersen
patent: 4134607 (1979-01-01), Koski
patent: 4629109 (1986-12-01), Matsushita
patent: 4948027 (1990-08-01), Yamashita et al.
Product brochure for Indulay® abrasion resistant chromium carbide welded overlay for piping products, Indutech Industrial Technology, Indutech Canada Limited, Calgary, Alberta, Canada, 4 pages, date prior to Sep. 14, 1999.
Product brochure for Brospec Fusionbond Plate and Pipe, Brospec Inc., Quebec, Canada, 12 pages, date prior to Sep. 14, 1999.
Product brochure for CF Ultra Tech Abrasion Resistant Piping Systems, CF Ultra Tech Inc., Grafton, Wisconsin, U.S.A., 4 pages, date prior to Sep. 14, 1999.
Harmat Fred
Van Dongen Graeme
Almac Machine Works Ltd.
Christensen O'Connor Johnson & Kindness PLLC
Johnson Jonathan
Ryan Patrick
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